AUTHOR=Takeda-Uchimura Yoshiko , Nishitsuji Kazuchika , Ikezaki Midori , Akama Tomoya O. , Ihara Yoshito , Allain Fabrice , Uchimura Kenji 

TITLE=Beta3Gn-T7 Is a Keratan Sulfate β1,3 N-Acetylglucosaminyltransferase in the Adult Brain

JOURNAL=Frontiers in Neuroanatomy

VOLUME=16

YEAR=2022

URL=https://www.frontiersin.org/journals/neuroanatomy/articles/10.3389/fnana.2022.813841

DOI=10.3389/fnana.2022.813841

ISSN=1662-5129

ABSTRACT=<p>Keratan sulfate (KS) glycan is covalently attached to a core protein of proteoglycans. KS is abundant in neuropils and presents densely in close proximity to the perineuronal region of the perineuronal net-positive neurons in the adult brain under physiological conditions. We previously showed that the synthesis of KS positive for the R-10G antibody in the adult brain is mediated by GlcNAc-6-sulfotransferase 3 (GlcNAc6ST3; encoded by <italic>Chst5</italic>). Deficiency in both GlcNAc6ST3 and GlcNAc6ST1, encoded by <italic>Chst2</italic>, completely abolished KS. Protein-tyrosine phosphatase receptor type z1 (Ptprz1)/phosphacan was identified as a KS scaffold. KS requires the extension of GlcNAc by β1,3 <italic>N</italic>-acetylglucosaminyltransferase (Beta3Gn-T). Members of the Beta3Gn-T family involved in the synthesis of adult brain KS have not been identified. In this study, we show by a method of gene targeting that Beta3Gn-T7, encoded by <italic>B3gnt7</italic>, is a major Beta3Gn-T for the synthesis of KS in neuropils and the perineuronal region in the adult brain. Intriguingly, the <italic>B3gnt7</italic> gene is selectively expressed in oligodendrocyte precursor cells (OPCs) and oligodendrocytes similar to that of GlcNAc6ST3. These results indicate that Beta3Gn-T7 in oligodendrocyte lineage cells may play a role in the formation of neuropils and perineuronal nets in the adult brain through the synthesis of R-10G-positive KS-modified proteoglycan.</p>